Steam generator



2 Sheets-Sheet l E B PETRIE STEAM GENERATOR Filed May 15, 1922 Dec. 13, 1927.

Patented Dec. 13, 1927,.

UNITED STATES resazsz PATENT ore-ion.

ENDS B. PETRIE, 033 SOUTH BROOKLYN, NEW YORK.

i STEAM GENERATOR.

Application filed May 15 This invention a steam generator and the object of the invention is to provide boiler construction which novel and efficient in the carrying out oi its purposes and embodying novel peculiarities'which enable it to effect rapid vaporization and the superheating of such evolved vapors with econ only and expedition so that relatively small boilers may be employed for furnishing a comparatively large amount of steam under high pressure.

The boiler of this invention embodies a plurality of heating elements each o't which comprises concentric annular tubes between which are formed annular spaces into which the water to be converted into steam is in troduced. Heat to eltect this conversion is supplied interiorly of the inner tube and in the preferred form of the invention from an electric resistance housed within the in ner tube. When electric current is passed through such resistance it becomes highly heated and the heat emanating therefrom serves to convert the water contained in the annular space into steam. The steam finds exit "from the annular space into a boiler or steam space where'it desired it may be superheated and is thereafter passed to its work. One or more heating elements of the character described may be employed with each boiler or steam space and these ele ments may project through the stenrspace or may be positioned exterior-1y thereof.

Features of the invention, other than those specified, will be apparent from the hereinafter detailed description and claims, when read in conjunction with the accompanying drawings.

The accompanying drawings illustrate one different practical embodiment of the invention but the construction therein shownare to be understood as illustrative, only, and not as defining the limits of the invention.

Figure l is an end view of a boiler entbodying the present invention.

Figure 2 is a section on the line 2-2 oi Figure l; and, s

Figure 3 is a 'lragmental section showing a modified term of heating element.

Referring to the drawings, 1 designates a heating element. This element embodies a pair of coaxial tubes 2 and 3, the inner tube 3 being externally threaded and the outer tube 2 being both interiorly and ex teriorly threaded. The inner tube 3 is reduced intermediate itsv ends so that when the 1922. Serial No. 561,142.

tube 3 is screwed into the tube .2, an annular space 4 will be left between the tubes which space will extend for substantially the en tire length ot both tubes. The tube 2 is somewhat longer than the tube 8, so that after the latter has been screwed into the Ltormer, threaded heating heads 5 may be screwed Into the opposite ends ofthe tube 2 for the purpose of closing the ends of the inner tube. Water is introduced into the annular space a adjacent one end thereof through a pip and is heated in said space by heat generated within the interior of the inner tube in Figure 3 oi the drawings, the heat is shown as supplied from a burner or n ector tube T, which extends througl'i at least one of the heating heads 5, so as to in ect gaseous or liquid fuel into the interior ot the inner tube 3 to generate the heat desired. In Figure 2, however, the heat is produced by electric current which is passed through a resistance 8 extending longitudinally through the inner tube and fed by wire leads 9, which pass through the heating heads 5 and are insulated therefrom as shown at 10.

in the construction of Figure 2, the heating heads 5 may be vented as at 11, while in the construction shown in Figure 3, the waste products 01'' combustion are preterablv lead or? to a stack through the opposite end of the inner tube from that intd which the fuel is introduced.

The heatgenerated within the inner tube either through flame or through the heat of an electric resistor converts the water in the annular space 4 intosteain and this conversion is eihcientand Xpeditious since only a relatively thin annularcoluinn of water is subjected to a relatively large heating suri ace; 1n practice the inner tube may be heated to such extent and the How of water into such tube so controlled that the heat will constitute substantially a flash heater That is to say, the water will be converted into steam as soon as it is introduced into the chamber.

However in pectice, l preferably maintain the space l about half full of water, this being controlled in any suitable manner and may be observed by means of suitable sight tubes associated. with the heating element.

The steam evolved in the space finds exit through a pipe 12 which terminates within steam space or boiler shell 13 with this boiler shell 13 may be associated any number of heating elements of the character described. In Figure 2, five of such elements are illustrated as associated with the boiler 13. Three of which heaters pass through the boiler and two of the heaters being positioned exterior-1y of the boiler. Gauge glasses 14: are shown as associated with the exteriorly positioned heating elements though similar glasses may also be associated with the three interiorly positioned heating elements.

The steam outlet pipes 12 of the exteriorly positioned heaters extend through the wall of the boiler into the interior there of and a point preferably well toward the top of the boiler, while the steam pipe 12 of the interiorly positioned elements extends upwardly interiorly of the boiler as shown in dotted lines in Figure 2.

The exteriorly positioned heating elements may be mounted on the boiler in any suitable manner, but the interiorly positioned elements preferably extend through the end walls of the boiler and are clamped to said end walls by means of nuts 15 and 1G positioned respectively on the interior and exterior of the end walls and threaded upon the exterior threads of the outer tube 2, so as to clamp the end walls of the boiler firmly between the nuts and form a tight and leak proof joint. This construction not only serves to adequately preclude leakage and form a rigid mounting for the heaters, but it will be also apparent that the clamping of the end walls of the boiler to the heating elements impart to the heating elements the function of stay bolts which greatly reinforce the end plates and produce a strong and rigid construction.

The boiler may be additionally provided with stay bolts 1 should this be considered.

necessary.

The steam from both the exteriorly and interiorly positioned heating elements is fed into the steam space within the boiler 18 and if desired may be superheated by means of a superheating element 18 embodying a single tube provided with clamping nuts 19 and 20 for rigidly mounting it in the end plates of the boiler and the opposite ends of which tube are closed by heating heads 21. The tube 18 encloses an electric resistance 22, the leads 23 of which extend through the heads 21 and are insulated therefrom as at 24. In this construction the tube 18 may be raised to a high temperature for the purpose of super-heating the steam within the boiler 13, after such steam is passed from the primary heating elements into the steam space of the boiler. In practice, any number of superheating elements may be employed, but for the purpose of illustration, I have shown only one in Figures 1 and :2 of the drawings. In order that the boiler may be properly safeguarded, a safety valve 25 of any conventional type may be associated therewith and a blow-off valve 26 for facilitating the blowing off of the boiler and a pressure gauge 27 are also provided, as shown in Figure 1.

In the foregoing description, I have set forth the preferred practical, form of the present invention. It will be understood however that details in construction may be modified, as by the substitution of equiva lents without departing from this invention, the scope of which is commensurate with the appended claims.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. A steam generator embodying a boiler shell, an outer tube extending through the boiler shell and having its opposite ends anchored in the opposite ends of the boiler shell, said tube being interiorly threaded and having a steam outlet communicating with the interior of the boiler shell, an inner tube provided with enlarged threaded end portions adapted to be screwed into the interior threads of the outer tube, said inner tube being shorter than the outer tube and of less exterior diameter between its enlarged end portions than the interior diameter of the outer tube to provide an annular cham-- ber between said tubes, means for introducing water into the annular chamber and an electric resistance positioned within the inner tube to heat said inner tube to a high temperature for the purpose of converting the water in the annular chamber into steam, and an outlet from said chamber leading into the steam space of the boiler shell.

2. A steam generator embodying a boiler shell, an outer tube extending through the boiler shell and having its opposite ends anchored in the opposite ends of the boiler shell, said tube being interiorly threaded and having a steam outlet communicating with the interior of the boiler shell, an inner tube provided with enlarged threaded end portions adapted to be screwed into the interior threads of the outer tube, said inner tube being shorter than the outer tube and of less exterior diameter between its enlarged end portions than the interior diameter of the outer tube to provide an annular chamber between said tubes, means for introducing water into the annular chamber, and an electric resistance positioned within the inner tube to heat said inner tube to a high tem perature for the purpose of converting the water in the annular chamber into steam which is adzuated to find exit into the steam space of the boiler shell, and separate and in dependent heating means for applying fun ther heat to the thus generated steam after it has entered the boiler space.

8. A. steam generator embodying a boiler shell, an outer tube extending through the lib) Ail

boiler shell and having its opposite ends anchored in the opposite ends of the boiler shell, said tube being interiorly threaded and having a steam outlet communicating With the interior of the boiler shell, an inner tube provided with enlarged threaded end por tions adapted to be screwed into the interior threads of the outer tube, said inner tube being shorter than the outer tube and of less exterior diameter between its enlarged end portions than the interior diameter 01' the outer tube to provide an annular chamber between said tubes, means for introducing Water into the annular chamber, and an electric resistance positioned Within the inner tube to heat said inner tube to a high temperature for the purpose of converting the Water in the annular chamber into steam, and an outlet from said chamber leading into the steam space of the boiler shell, another tube extending through the boiler shell and anchored at its opposite ends to the op posite ends of the boiler shell, and an electrical heating unit Within said tube for heating the tube for the purpose of further heating the steam after it has entered the boiler space.

l. A steam generator embodying a boiler shell, a plurality of steam generating units, each or which comprises an outer tube extending through the boiler shell and anchored at its opposite ends to the opposite ends of the boiler shell and having a steam outlet to the interior of the boiler shell, an inner tube Within the outer tube and spaced therefrom intermediate its ends to provide a steam generating chamber closed except for the outer tube to the boiler space, a Water inlet to said chamber, and heating means for interiorly heating the inner tube for converting Water in the steam chamber into steam, whereby the said steam passes into the boiler space and is housed therein.

5., A. steam generator embodying a boiler shell, a plurality of steam generating units,

each of Which comprises an outer tube extending through the boiler shell and an chored at its opposite ends to the opposite ends of the boiler shell and having a steam outlet to the interior 01; the boiler shell, an

the boiler space and is housed therein, in

combination With separate and independent means for applying further heat to the thus generated steam after it has entered the boiler space.

' A steam generator embodying a boiler shell, a plurality of steanr generating units, each of which comprises an outer tube ex tending through the boiler shell and anchored its opposite ends to the opposite ends of the boiler shell and having a steam outlet to the interior of the boiler shell, an inner tube within the outer tube and spaced therefrom intern'lediate its ends to provide a steam generating chamber closed except for the outer tube to the boiler space, a water inlet to said chamber, and heating means for interiorly heating the inner tube for converting Water in the steam chamber into steam, whereby the said steam passes into the boiler space and is housed therein, in combination with another tube extending through the boiler shell and anchored at its opposite ends to the opposite ends of the boiler shell, and an electrical heating unit Within said tube for heating the tube for the purpose of further heating the steam alter it has entered the boiler space.

In testimony whereof I have signed the foregoing specification.

ENDS B. PETRIE,

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